Dissociative and Contractile Reactions of Actomyosin With Uridine Triphosphate

Abstract

A comparison was made between the actions of UTP and of ATP upon the contractile response of a skeletal muscle model system and upon the viscosities of purified cardiac and skeletal actomyosin. It was found that UTP and ATP were approximately equivalent mole for mole in inducing contraction and relaxation in the muscle model. There is some difference in the dissociative action of ATP and of UTP upon the actomyosin which conceivably may be dependent on the rate of dephosphorylation of nucleotide by the protein.